1. Department of Soil Science, Federal University of Viçosa, Viçosa, Minas Gerais, Brazil
2. Department of Soil Science, Escola Superior de Agricultura Luiz de Queiroz, Grupo de Políticas Públicas, Piracicaba, São Paulo, Brazil;
3. Department of Geoscience, Institute of Geoscience, University of Brasília, Brasília, Brazil
4. Geography Department of Federal, University of Mato Grosso do Sul, Três Lagoas, Minas Gerais, Brazil
5. Department of Soil Science, "Luiz de Queiroz" College of Agriculture, University of São Paulo, Piracicaba, São Paulo, Brazil
6. Department of Geology and Natural Resources, Institute of Geosciences, University of Campinas, Campinas, CEP/São Paulo, Brazil